I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.
I think you are refering to the periodic table. The periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.
Answer:
I think the answer is B.
Explanation:
I think this because they have these variations to better adapt to conditions in their environments.
All of the following are forms of radiation except A. Stabilizing rays.
